1. Field of the Invention
The invention relates to the general field of methods and apparatus for replicating the characteristics of an original object such as a stone or stone panel in a cast article. More particularly, the invention relates to the field of such methods and apparatus further incorporating into the cast article useful shapes and properties not present in the original object but normally helpful in constructing commercial structures such as facades and walls from the cast articles.
2. Discussion of the Background
Many people have attempted to manufacture items simulating the contours and colors of an original object such as a natural article, but produce an item that either does not look authentic or poorly reproduces the original object in its entirety. One example is Formica®, a hard plastic substrate used to cover countertops and the like. Some forms of Formica® were impregnated during manufacture with dyes or other colored material to simulate the look of wood or stone. However, the simulation was not convincing because the Formica® was fiat. Also, it did not have the texture of the original object it purported to simulate.
Another example is Corian®. This was made from plastic in the form of sheets of varying thickness for use as countertops and related structures. Most forms of Corian® were made by mixing filler materials with plastic and the resulting product was colored much like the filler material used during manufacture. Some forms of Corian® were made to resemble stone. However, the simulation was not appealing because Corian® was largely fiat and it also did not have the texture of the natural articles it purported to simulate.
Yet another example is Linoleum®. This was made from various plastics and fillers and was sold in the form of sheets or rolls, principally for covering floors with a wear-resistant surface. While some forms of Linoleum® were colored and textured to resemble natural articles, the simulation was still not convincing. The colors were artificial and the texture so regular as to dispel the notion of a natural articles.
Still another example is plastic floor tiles. These were typically squares of regular size. They were intended to be butted against one another once a mastic had been applied, and some were both colored and textured to resemble natural articles. However, the colors were often unconvincing. Further, the same was true for the textures, which were not only shallow but also discontinuous where one tile butted up against another.
Another example is exterior siding designed to replace or cover some or all of the exterior of outdoor structures, including houses. This siding typically was made of plastic or aluminum and was marked or embossed in an effort to simulate natural articles. However, the simulation was not appealing. The colors were unconvincing and the textures were not only shallow and unrealistic but also discontinuous where one piece of siding butted up against another.
Another example is cultured stone. This was cast from cement and aggregate and simply mimicked the characteristics of real stone. It could not be molded any differently from the natural article and required the same methods for installation as real stone.
Processes for casting plastics are disclosed in U.S. Pat. No. 5,750,583 to Gansen et al. and U.S. Pat. No. 3,883,627 to Fitts. Gansen et al. disclosed a process for the preparation of polyurethane products in which a plastic film was positioned in a mold, the mold was closed, a polyurethane reaction mixture was injected into the mold, and the product was removed from the mold once the reaction mixture had fully reacted.
Fitts disclosed a process in which a heat curable elastomeric sheet comprising a curing agent and either urethane elastomeric gum stock or silicone gum stock was placed over a master to be copied. The heat curable elastomeric sheet was one that did not cause inhibition between the master and the heat curable elastomeric sheet. Next, the elastomeric sheet was vacuum drawn against the master and the master sheet material was enclosed in a frame. A foamed polymeric backing was then formed in situ to force the heat curable elastomeric sheet against the master to copy the shape of the master. The heat curable elastomeric sheet was then cured in the shape of the master. Finally, articles were molded in the shape of the master in a mold constructed from the cured elastomeric sheet material.
A decorative plastic moulding was disclosed in U.S. Pat. No. 5,372,869 to Drexinger et. al. The moulding comprised two moulding pieces, each with a decorative face, a back, two sides, and two ends. Each end of each piece had a 45 degree angle pre-mitered cut relative to the plane of the decorative face, with the pre-mitered cuts of each piece being in parallel planes. Each side of each piece was in a plane at a 45 degree angle to the plane of the decorative face, with the side planes converging at a position spaced from the back of the piece. The two moulding pieces were made of fire rated polyurethane.
Finally, a method for molding an artificial rock was disclosed in U.S. Pat. No. 4,940,558 to Jarboe et. al. This method entailed selecting a rock for reproduction and creating a flexible rubber mold and supporting cradle having a mold cavity conforming to the exterior of the rock. The mold has a substantial degree of flexibility and is created by applying an uncured liquid rubber forming material to the rock and curing the uncured liquid rubber forming material to produce the rubber mold. The cradle is formed by applying or spraying a low density urethane foam forming mixture to the exterior of the rubber mold to provide a self-supporting cradle and spraying a two-sided urethane composition into the mold cavity. The urethane composition comprises an isocyanate side and a polyol side and is mixed in a spray gun in a spray-in-mold process to build up the molded artificial rock to a desired thickness. The cradle and mold are then stripped away after curing.